The present invention relates to vapor handling systems in a fueling environment, and more particularly, to a centralized vapor recovery site management controller configured to receive information from various devices in the fueling environment and make logical decisions based on the received information to maximize the vapor recovery efficiency of the site.
Distributed, assist vapor recovery systems, such as Gilbarco, Inc.'s Vapor Vac.RTM. system are used to recover hydrocarbon vapors that normally escape to the atmosphere from vehicle tanks during refueling and return these vapors to the underground storage tank. Most of these assist vapor recovery systems have a vapor recovery rate that is a function of the fuel delivery rate of the dispenser.
These vapor recovery systems are tested and certified by the California Air Resources Board (CARB) and other regulatory agencies. This testing requires each system to be tested for vapor recovery efficiency during refueling popular make and model cars. For example, the current CARB test requires that each vapor recovery system be tested on 100 popular model cars. The amount of vapor recovered and vapor lost during the testing is used to determine efficiency.
Because of variations in vehicle fuel neck designs, the recovery efficiency of the fuel neck will vary considerably. The objective in obtaining CARB certification is to tune the assist systems recovery algorithm to achieve 95% efficiency when measured over the vehicles and the certification test. Another major variable that will have a dramatic effect on overall site efficiency is equipping vehicles with onboard vapor recovery systems (ORVR). ORVR equipment vehicles were introduced with the 1988 model year and will be phased into almost all vehicles over the next nine years. When fueling an ORVR equipped vehicle, most vapors will be retained in the vehicle, and the assist vapor recovery system, if unmodified, will pump air into the fuel storage tank. The net effect will be to increase storage tank pressure causing so-called "fugitive" emissions. A number of systems have been developed to deal with these emissions.
With the implementation of digital electronic control into vapor recovery system designs, it is possible to establish the best vapor recovery vapor/liquid (V/L) ratio or curve for each model vehicle tank and filler neck design, among other variables, and store them in memory in the vapor recovery system. It is also possible to add a smart card or transponder-type device to the vehicle to communicate with the dispenser and provide the dispenser with information necessary to select an appropriate vapor recovery algorithm for the vehicle. For further information regarding specific control of vapor recovery based on ORVR detection, see U.S. Pat. No. 5,782,275 the content of which is hereby incorporated herein by reference.
Each of the systems described above operates independently of each other without accounting for its effect on the other. Up to this point no central control device has been provided to coordinate the separate efforts of these systems so as to monitor and/or maintain a particular site's V/L ratio. Additionally, there has been no effort to monitor and control the total vapor emissions level for a particular site. The present invention addresses these and also other problems that may not be specifically detailed herein.